Roofing products are often divided into three broad groups: shingles, roll roofing and underlayment. Shingles and roll roofing typically function as outer roof coverings designed to withstand exposure to weather and the elements. In a typical roof installation, the underlayment is first laid on top of the roof deck, and then the outer roofing covering (e.g., shingles or roll roofing) is attached on top of the underlayment. Asphalt shingles and roll roofing generally contain the same basic components which provide protection and long term wear associated with asphalt roofing products. Asphalt shingles (sometimes also referred to as composite shingles) are one of the most commonly used roofing materials. Asphalt shingles may include an organic felt or fiberglass mat base on which an asphalt coating is applied. The organic felt or fiberglass mat base gives the asphalt shingle the strength to withstand manufacturing, handling, installation and servicing activities, and the asphalt coating provides resistance to weathering and stability under temperature extremes. An outer layer of mineral granules is also commonly applied to the asphalt coating to form a weather surface which shields the asphalt coating from the sun's rays, adds color to the final product, and provides additional fire resistance.
Asphalt shingles are typically manufactured as single layer shingles, strip or three tab shingles, multiple layer shingles, laminated shingles, interlocking shingles, and large individual shingles in a variety of weights and colors.
Various asphalt shingles have been developed to provide an appearance of thickness and texture comparable to wood shingles. Examples of such asphalt shingles are shown in U.S. Pat. No. 5,232,530 entitled “Method of Making a Thick Shingle”; U.S. Pat. No. 3,921,358 entitled “Composite Shingle”; U.S. Pat. No. 4,717,614 entitled “Asphalt Shingle”; and U.S. Pat. Des. No. D309,027 entitled “Tab Portion of a Shingle.” Some laminated asphalt shingles simulate the appearance of slate roofing shingles. See U.S. Pat. No. Des. 369,421. Each of the patents mentioned in this paragraph is incorporated by reference herein in its entirety.
In addition to these patents, significant improvements in the art of roofing shingles have been disclosed and patented in U.S. Pat. Nos. 5,369,929; 5,611,186; and 5,666,776; each entitled “Laminated Roofing Shingle”, issued to Weaver et al. and assigned to the Elk Corporation of Dallas. These patents disclose laminated roofing shingles developed to create the illusion of thickness or depth on a relatively flat surface by including a backer strip having striations of color beneath and between tabs wherein the color is uniform within the tab. Each of these three patents is also incorporated by reference herein in its entirety.
Further improvements include the use of larger shingles having a buttlap section of greater than about 7 inches to provide a more pleasing appearance and a greater visual impact by providing enhanced dimensionality, as disclosed in pending U.S. patent application Ser. No. 09/401,392 entitled “Laminated Roofing Shingle” and filed on Sep. 22, 1999, which is incorporated herein by reference in its entirety. Shingles typically have a buttlap section, a part of which is exposed to the environment, and a headlap section, which is covered by the buttlap section of the shingle in the next row above. The headlap section is typically wide in order to (i) provide waterproofing, (ii) insure that a majority of the roof is covered by at least one layer of buttlap section and at least one layer of headlap section, and (iii) aid in the production and handling of the shingle.
All of the aforementioned roofing products require the use of an underlayment which is applied to cover the deck of a roof before the application of roofing shingles or other roofing material. Its primary purpose is to shield the roof deck from moisture, both during assembly and after roof installation. Underlayment also helps reduce “picture framing” in which the outline of deck panels caused by irregularities in the deck surface may be visible through the roofing material applied to the roof deck. Further, it is desired that roofing underlayment be a key component of a fire rated roof assembly. The underlayment structure should assist in preventing flaming of the underside of the deck when exposed to fire on top of the roof covering assembly. Thus, the benefits of the underlayment in the roof assembly are to provide additional water resistance and fire resistance, and to provide uniformity of the appearance of the roof surface.
Roofing underlayment typically comprises a dry cellulosic felt that can be impregnated or saturated with an organic material such as asphalt. When used as an underlayment, felt typically does not provide a completely flat surface, but has wrinkles, undulations, and distortions. It may also distort under high moisture conditions. Saturated organic felt underlayment has poor fire resistance and when burned, disintegrates.
Traditional underlayments are vulnerable to damage before the protective roofing material is laid down. For example, traditional underlayments can be damaged by workers walking on the underlayment or by items, such as tools, dropped on the underlayment. Ripped or torn underlayment will not serve as an effective waterproofing barrier and must be patched before the roofing material (e.g. roofing shingles or roll roofing) can be laid down.
U.S. Pat. No. 6,500,560, which is assigned to the assignee of the present invention and is incorporated in its entirety herein by reference, provides a roofing underlayment which is an asphalt coated structural article comprising a substrate having an ionic charge coated on one side with a layer of asphaltic material and coated on the other side with a coating having essentially the same ionic charge as the substrate. It may be used as a roofing underlayment for concrete tiles or to waterproof the basement walls of a building structure.
U.S. patent application Ser. No. 09/663,255, filed on Sep. 15, 2000, which is assigned to the assignee of the present invention and is incorporated herein by reference in its entirety, relates to a roofing underlayment system useful in roof assemblies comprising at least two layers of a coated structural article which comprises a substrate having an ionic charge coated with a coating having essentially the same ionic charge, or at least one layer of such coated structural article in combination with at least one layer of felt material.
Roofing underlayment and roofing materials are typically installed on a roof deck with fasteners such as nails. However, there are roofing underlayments available which have an adhesive on one side and can be installed on a roof by adhering the underlayment to the roof. Examples of such underlayments include the underlayment described by U.S. Pat. No. 6,500,560. In addition, self-adhesive peel and stick membranes which can be used as underlayments are available from Malarkey (Pleasanton, Calif.; Right Start™ and Arctic Seal™ Peel & Stick), Polyglass USA (Hazleton, Pa.; Polystick™ IR-X, Polystick™ P, Polystick™ TU and Polystick™ MU) WR Grace (Columbia, Md.; Ice & Water Shield™), Georgia-Pacific (Atlanta, Ga.; Tough-Guard™), Tamko (Joplin, Md.; TW Metal & Tile Underlayment, TW-60, TW Flash-n-Wrap™, TW Moisture Wrap™, TW Moisture Guard, and Bridgeguard™), GAF (Wayne, N.J.; WeatherWatch®, StormGuard®, MetalMate™), and Certainteed (Valley Forge, Pa.; Black Diamond™ base sheet).
While the use of a separate underlayment installed prior to the installation of roofing materials has been an acceptable means for achieving the desired effects (i.e. additional water resistance and fire resistance, and to enhance uniformity of the appearance of the roof surface), a roofing composite that provides the function of a roofing underlayment and the roofing material in a single product, and that enables easier installation would be desirable.
U.S. patent application Ser. No. 10/211,663, incorporated in its entirety herein by reference, and which is assigned to the assignee of the present invention, discloses a composite roofing product which comprises a roofing material and an interply material attached to the roofing material. The interply material is an underlayment-type material which is water resistant and replaces the headlap portion of the shingle. However, the roofing product of U.S. patent application Ser. No. 10/211,663 requires the use of nails or other fasteners to secure it to the roof deck.